Ringworld

Ringworld is a 1970 SF novel by Larry Niven, set in his Known Space universe, which won the 1971 Best Novel Hugo.

Niven later added four sequels and four prequels. The Fleet of Worlds series, co-written with Edward M. Lerner, provides the four prequels as well as Fate of Worlds, the final sequel. These books tie into numerous other books set in Known Space.

Ringworld also won the Nebula Award in 1970 and a Locus Award in 1971.